Method of and dies for forming sheet-metal cones



(N0 Model.)

P. HART. METHOD OF AND DIES FUR FORMING SHEET METAL CONBS.

No. 469,785. Patented Mar. 1,1892.

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UNITED 'STATES PATENT OFFICE.

FREDERICK HART, .OF POUGHKEEPSIE, ASSIGNOR TO D. H. BURRELL & CO., OF LITTLE FALLS, NEV YORK.

METHOD OF AND DIES FOR FORNIlNG SHEET-METAL CONES.

SPECIFICATION forming part of Letters Patent No. 469,785, dated March 1, 11892.

Application iiled May 29, 1891. Serial No. 394,544. (No model.)

To all whom t may concern:

Beit known that I, FREDERICK HART, a subject of the Queen of Great Britain, residing at Poughkeepsie, in the county ofDutchess and State of New York, have invented a new and useful Improvement in Methods of and' Dies for Forming Sheet-Metal Cones, of which the following is a specification.

This invention relates to the formation of cones and similarly-shaped articles of heavy sheet metal-for instance, the bottoms of centrifugal separators, which are provided with a raised central cone or hub. Heretofore it has been customary to form suchv cones by stamping the heated metal between two dies into the desired form, by which process of manufacture the metal is stretched. This man-ner of forming the cones which are used in the construction of centrifugal separators materially reduces the thickness of the metal, impairs its tensile strength, and renders it liable to be fractured under the great strains which result from the high velocity with which such separators are revolved.

The object of myinvention is to form such cones and similarly-shaped bodies out of sheet metal in such manner that the cone is gratinally thickened and compacted instead of being stretched and thinned; and the invention consists, to that end, of thenovel method and devices which Will be hereinafter fully described, and pointed out in the claims.

In the accompanying drawings, Figure l isa sectional elevation of a hydraulic press provided with the preliminary dies for stamping the blank into a concavo-convex form preparatory to forming the con e.v Figs. 2, 3, 4, 5, and 6 are vertical sections of a series of intermediate dies by which the cone is gradually contracted and shaped. Figs. 7 and 8 are vertical sections of the dies, whereby the cone is finished. Fig. 9 is a plan view of a finished cone as it is taken from the finishing-dies shown in Fig. 8.

Like letters of reference refer to like parts in the several iigures. l

A represents a hydraulic press of any suitable construction, having horizontal head and foot blocks B C, respectively connected by posts DD.

E represents the hydraulic cylinder` arranged in the foot-block C, and e the primary piston or ram arranged in the secondary piston e', both capable of moving vertically inside the hydraulic cylinder E.

F represents a male die having a moderate convex surface and mounted upon the upper end of the primary piston or ram e.

f represents an annular female die secured to the under side of the head-block B by bolts f and provided with a concavity correspondness, is heated and placed upon the male die.

The latter carries the heated disk upwardly into the female die and presses it into a concavo-convex form, as represented in Fig. l.

The form of the working faces ofthe prelimi-` nary dies Ff is such that the metal will be stretched by these dies as little as possible. After thepreliminary pressing of the disk has been effected, the preliminary dies are removed from the head-block 'and piston and the pair of dies H H represented in Fig. 2 are substituted for the preliminary dies. The cavity of the female die H is a trifle less inclined or tapered than the cavity of the preliminary female die. The male die H is provided with a horizontal circular bottom plate h, having la marginal flange 7L', projecting upwardly outside of the female die, and a socket 71.2, by which it is seated on the upper end of the primary ram or piston.

h3 represents a post or standard formed centrally on the bottom plate 71. and provided with a teat or pin adapted to engage in an opening in the head I of the male die, which is seated on the upper end of the post and holds the same against lateral movement. The upper end of the die-head I is made semispherical land of smaller diameter than the narrowest portion oft-he conical opening in the female die.

A quantity of water is placed in the basin formed on the plate 7i by the annular flange h. The conical blank formed by the preliminary dies is heated and placed over the male die H', so-thatthe marginal portion of the blank is immersed in the water and becomes cooled. The cooled marginal portion of the blank confines the heated central portion of the cone and causes the particles of metal in the heated portion to be crowded or swaged inwardly as the male die carries the cone up IOO into the female'die, which latter is of smaller diameter than the preliminary female die. Thelower horizontal facet' of the female die H in bearing upon the marginal portion of the blank causes it to be flatte ned and assume a horizontal position, thereby forming a flange g2 atthe base of the con e. The cooling-of the marginal flange is preferred, but not absolutely necessary, and in the succeeding four swaging and shaping operationsillustrated in Figs. 3, 4, 5, and 6 this process of cooling is omitted. At every successive step asmaller maledie-head I 121314 is placed upon the post h3 of the bottom plate, and female dies H2 H3 H4 H5 of correspondinglyreduced internal diameter are used in connection therewith. The apex of the cone is drawn downwardly at each swaging operation, and the height of the several male die-heads is correspondingly reduced, so as to leave a clear space between said heads and" theapex of the cone. The male die-heads andthe post supporting the same `may bedispeiisedwith;4 but it is desirable to use them for the purpose of guiding the cone-blank and' retaining the saine in place.

the cone increases the width of the annular flange g2'by degrees and diminishes the diameter ofthe cone. The cone is heated preparatory to every swaging operation. The external diameter of the bottom edge of the cone, as the latter is taken from the. preliminary dies,is practicallyr not increased during the successive operations of reducing the lcone to i'tsproper sizeas the particles of metalJ are forced inwardly-andn not outwardly. The height and diameter of the die-head` on the central post of the male die are so determined that the inner side of the cone will only come in contact with the die-head a short distance below the apex -of the coneso as toavoid the liability of stretching the metahwhich would be the case if the cone were supported on the apex of the male die. -As the cone becomes smaller it becomes correspondingly thicker and the metal composing it denser, and consequently more liable to spread the cooled flange which contines the heated metal. This, however, is compensated for by the flange g2, vwhich increases in radial width inwardly without perceptibly increasing its external-diameter as the cone decreases in diameter. After the cone has been successively heated and pressed iny the series of intermediate dies the cone is pressed successivelybetween two sets of finishing-dies. (Illustrated in Figs. 7 and S.) The same male portionJ is used lin both sets of finishing-dies and is provided with a `circular plate j. This male die is also provided withacentral conical studio, corresponding in height and shape to the conical' inner surface of the finishing cone. The female finishing-die L (shown in Fig. 7) presses the cone firmly against the As the centraln cavity ofthe female die becomes smaller and its taper straighter the horizontal facey t' of said die becomes correspondingly larger, and` in bearing` upon the lower inclined portion of A:in Fig. 8) is made to conform to the outer conical surface of the finished cone and presses the cone against the stud and finishes the same.

It is obvious that the form of the dies may be varied to alarge'extent andthat the number` of sets of'dies may be increased or diminished according to the nature of the metal to be pressed or shaped.

I claim as my invention- I 1. The herein-described methodof forming a hollow protuberance upon a flat plate without stretching the metal, which' consistsin heat-ing` the plate, bending itv toy an approxi- Vmately conical shape,.and then contracting the base portion of the cone by successivo compressing operationseffected from the outside inwardly against the side-of the tapering portion of the bent.plate,substantially as seti forth.

2. The herein-described methodfof swag-ing `or shaping metal, which consists in heating the blank, cooling the portion surrounding the portion to be swaged onshaped, andfswiag- 4ing or shaping the heatedL portion, whereby the chilled portion confines the heatedportion du ring the operation of 'swaging or shaping, substantially as set forth.

3. The herein-describedmethod of swaging or shaping metal, which consists in heating the blank, immersing the marginal portion of the blank in Water, andswaging or shaping the heated inner portion of the blank, substantially as set forth.

4. The herein-described method of forming a hollow protuberanee of increased thickness' of metal upon a flat plate, which consistsin-` heating the blank, cooling the marginal portion, and swaging or shaping the heated portion surrounded by the chilled portion, `subheated blank, substantially as set forth.

7. The combination, with the bottom plate of the male die having a stud arranged centrally on said bottom plate, of a detachable lfnead applied to said stud, substantiallyas set ort 1.

Witness my handl this'23d day of May, 1891.

FREDERICK HART.

Witnesses: l

J. S. VAN CLEEF, WILLIAM J. KENNnnY.

IOO 

